Question: Simplify the following expression: ${3(4-n)-3(-3n+1)}$
Explanation: Distribute the ${3}$ into the first set of parentheses: $ {3(}\gray{4-n}{)} - 3(-3n+1) $ $ {12-3n} - 3(-3n+1) $ Distribute the ${-3}$ into the parentheses: $ 12-3n {-3(}\gray{-3n+1}{)} $ $ 12-3n + {9n-3} $ Rewrite the expression to group the ${n}$ terms and numeric terms: $ {-3n + 9n} + {12 - 3}$ Combine the ${n}$ terms: $ {6n} + {12 - 3}$ Combine the numeric terms: $ {6n} + {9}$ The simplified expression is $6n+9$